public float Evaluate(float cosi)
{
cosi = LR.Clamp(cosi, -1.0f, 1.0f);
// Compute indices of refraction for dielectric
bool entering = cosi > 0.0;//>0 入射
float ei = eta_i, et = eta_t;
if (!entering)
{
LR.Swap(ei, et);
}
// Compute _sint_ using Snell's law
float sint = ei / et * (float)Math.Sqrt(Math.Max(0.0f, 1.0f - cosi * cosi));//处理溢出？
if (sint >= 1.0)
{
// Handle total internal reflection
return(1.0f);
}
else
{
float cost = (float)Math.Sqrt(Math.Max(0.0f, 1.0f - sint * sint));
return(BSDFFunction.FrDiel(Math.Abs(cosi), cost, ei, et));
}
}
public float Evaluate(float cosi)
{
return(BSDFFunction.FrCond(cosi, eta, k));
}
override public Spectrum rho(Vector w, int nSamples, float samples)
{
return(brdf.rho(BSDFFunction.otherHemisphere(w), nSamples, samples));
}
override public Spectrum f(Vector wo, Vector wi)
{
return(brdf.f(wo, BSDFFunction.otherHemisphere(wi)));
}
override public Spectrum Sample_f(Vector wo, Vector wi, float u1, float u2, float pdf)
{
Spectrum f = brdf.Sample_f(wo, wi, u1, u2, pdf); wi = BSDFFunction.otherHemisphere(wi); return(new Spectrum());
}
